Pressure vessels are commonly used for containing a variety of fluids under pressure, such as storing hydrogen, oxygen, natural gas, nitrogen, propane and other fuels, for example. Generally, pressure vessels can have any size or configuration. For example, the vessels can be heavy or light; single-use (e.g., disposable) or reusable; subjectable to high pressures (greater than 50 psi, for example) or low pressures (less than 50 psi, for example); and used for storing fluids at elevated or cryogenic temperatures.
Suitable composite container materials include laminated layers of wound fiberglass filaments or other synthetic filaments bonded together by a thermal-setting or thermoplastic resin. A polymeric or other non-metal resilient liner or bladder often is disposed within a composite shell to seal the vessel and prevent internal fluids from contacting the composite material, thereby serving as a fluid permeation barrier. During manufacture of a pressure vessel, the pressure vessel liner and the dispensing head for the composite fibers move in relation to one another in such a way as to wrap the fiber on the liner in a desired pattern. If the vessel is cylindrical, rather than spherical, fiber winding is normally applied in both a longitudinal (helical) and a circumferential (hoop) wrap. This winding process is defined by a number of factors, such as resin content, fiber configuration, winding tension, and the pattern of the wrap in relation to the axis of the liner.